Method and device for deriving inter-view motion merging candidate

ABSTRACT

The present invention provides a method and a device for deriving an inter-view motion merging candidate. A method for deriving an inter-view motion merging candidate, according to an embodiment of the present invention, can comprise the steps of: on the basis of encoding information of an inter-view reference block derived by means of a variation vector of a current block, determining whether or not inter-view motion merging of the current block is possible; and, if inter-view motion merging of the current block is not possible, generating an inter-view motion merging candidate of the current block by using encoding information of an adjacent block that is spatially adjacent to the inter-view reference block.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/126,028 filed Sep. 14, 2016, which is a U.S. National StageApplication of International Application No. PCT/KR2015/000450 filed onJan. 15, 2015, which claims the benefit under 35 USC 119(a) and 365(b)of Korean Patent Application No. 10-2014-0038097 filed on Mar. 31, 2014,in the Korean Intellectual Property Office, the entire disclosures ofwhich are incorporated herein by reference for all purposes.

TECHNICAL FIELD

The present invention generally relates to a method and device forderiving an inter-view motion merge candidate and, more particularly, toa method and device for deriving a motion merge candidate using theencoding information of a reference block so as to derive a motion mergecandidate for the current block.

BACKGROUND ART

The International Organization for Standardization (ISO)/InternationalElectrotechnical Commission (IEC) Moving Picture Experts Group (MPEG)and the Telecommunication Standardization Sector of the InternationalTelecommunications Union (ITU-T) Video Coding Experts Group (VCEG)organized a Joint Collaborative Team on Video Coding (JCT-VC) in 2010,and started to develop next-generation video standard technology, knownas High Efficiency Video Coding (HEVC), and then completed thedevelopment of this technology in January 2013. HEVC enables compressionefficiency to be improved by about 50% compared to H.264/AVC HighProfile, which was previously known to exhibit the highest compressionperformance among existing video compression standards.

Meanwhile, three-dimensional (3D) video vividly provides a user with astereoscopic experience as if he or she were viewing and sensing thereal world, through a 3D stereoscopic display device. As researchrelated to this technology, the development of 3D video standards iscontinually progressed by the Joint Collaborative Team on 3D VideoCoding Extension Development (JCT-3V), which is the jointstandardization group of ISO/IEC MPEG and VCEG. 3D video standardsinclude both an advanced data format, which may support the playback,etc. not only of stereoscopic video but also of auto-stereoscopic video,using actual video and depth information maps thereof, and technologystandards related to the advanced data format.

Further, 3D-HEVC, the standardization of which is under development as a3D extension of HEVC, may use a motion merge process as a predictionencoding tool. The motion merge process is a method for inheritingmotion information, derived from neighboring blocks of the currentblock, without change, and utilizing the inherited motion information asinformation about the motion of the current block. The motion mergeprocess in 3D-HEVC is based on HEVC.

Further, 3D-HEVC may use an inter-view motion merge process based onimages at multiple views. That is, in 3D-HEVC, motion information may bederived from a block at the position corresponding to that of thecurrent block (hereinafter referred to as a ‘reference block’) amongblocks in neighboring views.

However, 3D-HEVC is problematic in that when motion is uniform,information about the motion of the current block cannot be derived fromthe reference block, and thus an inter-view motion merge process cannotbe used.

Meanwhile, Korean Patent Application Publication No. 10-2013-7027419(entitled “Method and Apparatus of Motion and Disparity VectorPrediction and Compensation for 3D Video Coding”) discloses a method forobtaining a motion vector (MV)/motion vector predictor (MVP) or adisparity vector (DV)/disparity vector predictor (DVP) associated with askip mode, a merge mode or an inter mode for the block of the currentpicture in 3D video coding.

DISCLOSURE Technical Problem

An object of some embodiments of the present invention is intended toallow a reference block to inherit predetermined information, such asmotion information, from neighboring blocks that are spatially adjacentto the reference block and to utilize the inherited information for amotion merge process for the current block if the reference block isintra-coded when an inter-view motion merge process for the currentblock is performed.

However, the technical object intended to be accomplished by the presentembodiments is not limited to the above-described technical object, andother technical objects may be present.

Technical Solution

In order to accomplish the above object, a method for generating aninter-view motion merge candidate according to an embodiment of thepresent invention includes determining whether an inter-view motionmerge process is possible for a current block based on encodinginformation of an inter-view reference block derived through a disparityvector of the current block; and if it is determined that the inter-viewmotion merge process is impossible for the current block, generating aninter-view motion merge candidate for the current block using encodinginformation of a neighboring block that is spatially adjacent to theinter-view reference block. Further, a device for generating aninter-view motion merge candidate according to an embodiment of thepresent invention includes a block search unit for individuallyacquiring encoding information from an inter-view reference block,derived through a disparity vector of a current block and at least oneneighboring block that is spatially adjacent to the reference block, aninformation analysis unit for determining whether an inter-view motionmerge process is possible for the current block based on encodinginformation of the inter-view reference block, and a candidategeneration unit for, if it is determined that the inter-view motionmerge process is impossible for the current block, generating aninter-view motion merge candidate for the current block using encodinginformation of the neighboring block.

In addition, the method for generating an inter-view motion mergecandidate may further include, if it is determined that the inter-viewmotion merge process is possible for the current block, generating aninter-view motion merge candidate for the current block using theencoding information of the inter-view reference block.

Further, determining whether the inter-view motion merge process ispossible for the current block based on the encoding information of theinter-view reference block derived through the disparity vector of thecurrent block may be configured to determine whether the inter-viewreference block is intra-coded, based on the encoding information of theinter-view reference block.

Furthermore, generating the inter-view motion merge candidate for thecurrent block using encoding information of the neighboring block thatis spatially adjacent to the inter-view reference block if it isdetermined that the inter-view motion merge process is impossible forthe current block, may be configured to generate the inter-view motionmerge candidate using encoding information of a highly correlatedneighboring block that is included in an object region including thereference block, among multiple neighboring blocks that are spatiallyadjacent to the inter-view reference block.

Furthermore, generating the inter-view motion merge candidate for thecurrent block using encoding information of the neighboring block thatis spatially adjacent to the inter-view reference block if it isdetermined that the inter-view motion merge process is impossible forthe current block, may be configured to generate the inter-view motionmerge candidate using encoding information of a highly correlatedneighboring block that is determined depending on inheritance priority,among multiple neighboring blocks that are spatially adjacent to theinter-view reference block, and the inheritance priority may be presetdepending on a sequence of encoding of the inter-view reference blockand individual neighboring blocks.

Here, the highly correlated neighboring block may be a neighboring blockthat is encoded subsequent to the inter-view reference block.

Furthermore, the candidate generation unit may be configured to, if itis determined that the inter-view motion merge process is possible forthe current block, generate an inter-view motion merge candidate for thecurrent block using the encoding information of the inter-view referenceblock.

Furthermore, the information analysis unit may determine whether theinter-view reference block is intra-coded, using the encodinginformation of the inter-view reference block.

Here, the information analysis unit may perform a determination withreference to a header including a flag that indicates whether theencoding information is used.

Furthermore, the header may be a video parameter set extension.

Furthermore, the encoding information of the reference block may includedepth information and motion information of the reference block, and theencoding information of the neighboring block may include depthinformation and motion information of the neighboring block.

Furthermore, the candidate generation unit may generate the inter-viewmotion merge candidate using encoding information of a highly correlatedneighboring block that is included in an object region including thereference block, among multiple neighboring blocks that are spatiallyadjacent to the inter-view reference block.

Furthermore, the candidate generation unit may generate the inter-viewmotion merge candidate using encoding information of a highly correlatedneighboring block that is determined depending on inheritance priority,among multiple neighboring blocks that are spatially adjacent to theinter-view reference block, and the inheritance priority is preset in asequence of the inter-view reference block, a neighboring block encodedsubsequent to the inter-view reference block, and a neighboring blockencoded prior to the inter-view reference block.

Advantageous Effects

In accordance with the technical solution of the present invention, thepresent invention uses a method for deriving motion information from theneighboring block of an inter-view reference block when an inter-viewmotion merge candidate cannot be derived. Therefore, the presentinvention may improve the encoding efficiency of a motion merge processwhen 3D video is encoded. Further, the present invention may reducecomputation complexity and memory complexity when decoding is performed.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing an embodiment of a video encoder;

FIG. 2 is a block diagram showing an embodiment of a video decoder;

FIG. 3 illustrates the case where the generation of an inter-view motionmerge candidate is impossible in the conventional method;

FIG. 4 illustrates an example of an intra-coded block;

FIG. 5 is a block diagram showing a device for generating an inter-viewmotion merge candidate according to an embodiment of the presentinvention;

FIG. 6 is a diagram showing the application of a method for generatingan inter-view motion merge candidate according to an embodiment of thepresent invention;

FIG. 7 is a flowchart showing a method for generating an inter-viewmotion merge candidate according to an embodiment of the presentinvention;

FIG. 8 is a diagram showing the application of a method for generatingan inter-view motion merge candidate according to another embodiment ofthe present invention; and

FIG. 9 is a flowchart showing a method for generating an inter-viewmotion merge candidate according to another embodiment of the presentinvention.

BEST MODE

Embodiments of the present invention are described with reference to theaccompanying drawings in order to describe the present invention indetail so that those having ordinary knowledge in the technical field towhich the present invention pertains can easily practice the presentinvention. However, the present invention may be implemented in variousforms, and is not limited by the following embodiments. In the drawings,the illustration of components that are not directly related to thepresent invention will be omitted, for clear description of the presentinvention, and the same reference numerals are used to designate thesame or similar elements throughout the drawings.

Further, throughout the entire specification, it should be understoodthat a representation indicating that a first component is “connected”to a second component may include the case where the first component iselectrically connected to the second component with some other componentinterposed therebetween, as well as the case where the first componentis “directly connected” to the second component. Furthermore, it shouldbe understood that a representation indicating that a first component“includes” a second component means that other components may be furtherincluded, without excluding the possibility that other components willbe added, unless a description to the contrary is specifically pointedout in context.

Detailed embodiments of the present invention will be described indetail with reference to the attached drawings. However, the spirit ofthe present invention is not limited to the presented embodiments, andother embodiments may be easily devised via additions, modifications,deletion or insertion of components within the scope of the same spiritas that of the present invention, but it may be understood that theother embodiments may also be included in the scope of the presentinvention.

Throughout the present specification, a representation indicating that afirst component “includes” a second component means that othercomponents may be further included, without excluding the possibilitythat other components will be added, unless a description to thecontrary is specifically pointed out in context. The term “step ofperforming ˜” or “step of ˜” used throughout the present specificationdoes not mean the “step for ˜”.

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the attached drawings.

Further, all of the methods and devices disclosed in the embodiments ofthe present invention may be applied both to encoding and decodingprocedures performed in a video processing procedure, and the term‘coding’ used throughout the present specification is a higher conceptincluding both encoding and decoding procedures. In addition, thoseskilled in the art may easily understand a decoding procedure withreference to the description of an encoding procedure, and vice versa.

Here, ‘encoding’ means a procedure for transforming the form or formatof video into another form or format for standardization, security,compression, or the like. Further, ‘decoding’ means a conversionprocedure for restoring the form or format of encoded video to itsoriginal form or format before being encoded.

Hereinafter, an encoder 100 and a decoder 200 will be described indetail with reference to FIGS. 1 and 2, respectively.

FIG. 1 is a block diagram showing an example of a video encoder 100.

Referring to FIG. 1, the video encoder 100 may include a prediction unit110, a subtractor 120, a transform unit 130, a quantization unit 140, anencoding unit 150, an inverse quantization unit 160, an inversetransform unit 170, an adder 180, and memory 190.

The prediction unit 110 generates a predicted block by predicting thecurrent block, which is desired to be currently encoded in video. Thatis, the prediction unit 110 may generate a predicted block havingpredicted pixel values from the pixel values of respective pixels in thecurrent block depending on motion information that is determined basedon motion estimation. Further, the prediction unit 110 may transferinformation about a prediction mode to the encoding unit so that theencoding unit 150 encodes information about the prediction mode.

The subtractor 120 may generate a residual block by subtracting thepredicted block from the current block.

Further, the transform unit 130 may transform respective pixel values ofthe residual block into frequency coefficients by transforming theresidual block into a frequency domain. For example, the transform unit130 may transform a video signal in a time domain into a video signal ina frequency domain based on a transform method such as a Hadamardtransform or a discrete cosine transform-based transform.

The quantization unit 140 may quantize the residual block transformedinto the frequency domain by the transform unit 130.

Further, the encoding unit 150 may encode the quantized residual blockbased on a coding technique and may then output a bitstream. Here, thecoding technique may be an entropy coding technique. Further, theencoding unit 150 may also encode the information about the predictionmode of the current block, transferred from the prediction unit 110,together with the residual block.

The inverse quantization unit 160 may inversely quantize the residualblock, which has been quantized by the quantization unit 140. That is,the inverse quantization unit 160 may transform the residual block,which has been transformed into the frequency domain, by inverselyquantizing the quantized residual block in the frequency domain.

The inverse transform unit 170 may inversely transform the residualblock, which has been inversely quantized by the inverse quantizationunit 160. That is, the inverse transform unit 170 may reconstruct theresidual block in the frequency domain as a residual block having pixelvalues. Here, the inverse transform unit 170 may use the transformmethod performed by the transform unit 130 by inversely performing thetransform method.

The adder 180 may reconstruct the current block by adding the predictedblock, generated by the prediction unit 110, to the residual block,which has been inversely transformed and reconstructed by the inversetransform unit 170. Further, the reconstructed current block is storedin the memory 190, and the reconstructed current block, which is storedin the memory 190, may be transferred to the prediction unit 110 and maybe utilized to predict a subsequent block using the correspondingreference block.

Meanwhile, the video encoder 100 may further include a deblocking filter(not shown). The deblocking filter (not shown) may function to improvethe video to realize higher-quality video before storing the currentblock, reconstructed by the adder 180, in the memory.

FIG. 2 is a block diagram showing an example of a video decoder 200.

Referring to FIG. 2, the video decoder 200 may extract a residual blockand prediction mode information, which are present before being encodedby the video encoder 100, by decoding a bitstream. The video decoder 200may include a decoding unit 210, an inverse quantization unit 220, aninverse transform unit 230, an adder 240, a prediction unit 250, andmemory 260.

The decoding unit 210 may reconstruct an encoded residual block andencoded motion information for the current block from an inputbitstream. That is, the decoding unit 210 may reconstruct a residualblock, encoded based on a coding technique, as a quantized residualblock. For example, the coding technique used by the decoding unit 210may be an entropy coding technique.

The inverse quantization unit 220 may inversely quantize the quantizedresidual block. That is, the inverse quantization unit 220 mayreconstruct the quantized residual block as a residual block transformedinto the frequency domain by inversely quantizing the quantized residualblock.

The inverse transform unit 230 may reconstruct the inversely quantizedresidual block, reconstructed by the inverse quantization unit 220, asthe original residual block by inversely transforming the inverselyquantized residual block. Here, the inverse transform unit 230 mayperform an inverse transform by inversely performing a transformtechnique used by the transform unit 130 of the video encoder 100.

The prediction unit 240 may predict the current block and generate apredicted block based on the motion information of the current block,which is extracted from the bitstream and decoded and reconstructed bythe decoding unit 210.

The adder 250 may reconstruct the current block by adding the predictedblock to the reconstructed residual block. That is, the adder 250 mayreconstruct the current block by adding predicted pixel values of thepredicted block, which is output from the prediction unit 240, to theresidual signal of the reconstructed residual block, which is outputfrom the inverse transform unit 230, and by then obtaining thereconstructed pixel values of the current block.

The current block reconstructed by the adder 250 may be stored in thememory 260. Further, the stored current block may be stored as areference block and may be used by the prediction unit 240 to predict asubsequent block.

Below, the conventional method for generating an inter-view motion mergecandidate will be described in detail with reference to FIG. 3.

In the conventional method of FIG. 3, the case where the generation ofan inter-view motion merge candidate is impossible is illustrated.

Referring to FIG. 3, the conventional method for generating aninter-view motion merge candidate may search for a reference block 311in a previous view frame 310, corresponding to the current block 321,which is the block desired to be currently encoded in the previous viewframe 320, with respect to the current block 321. In this case, theconventional method for generating an inter-view motion merge candidatemay use a disparity vector 130 based on a disparity required to correctpositions in different view frames. Further, the conventional method forgenerating an inter-view motion merge candidate may use an inter-viewmotion merge candidate for the current block 321, inherited from themotion information of the reference block 311.

However, the conventional method for generating an inter-view motionmerge candidate cannot inherit motion information from the referenceblock 311 if the reference block 311 is representatively intra-codedwhen an inter-view motion merge candidate for the current block 321 isgenerated. Therefore, the conventional method for generating aninter-view motion merge candidate cannot use an inter-view motion mergemethod.

Meanwhile, FIG. 4 illustrates an example of an intra-code block.

Referring to FIG. 4, when the current block X2′ is encoded, the currentblock X2′ may refer to the encoding information of neighboring blocks,which are spatially adjacent to the current block X2′. In particular,when the current block X2′ is encoded, the current block X2′ may referto blocks A21, A22, A23, B21, and C21, which are encoded prior to thecurrent block X2′.

However, in FIG. 4, since the object region to which upper blocks A21,A22, A23, B21, and C21 belong and the object region 420 to which thecurrent block X2′ belongs in the corresponding frame 410 are differentfrom each other, the current block X2′ of FIG. 4 has a lower correlationwith the upper blocks A21, A22, A23, B21, and C21.

As a result, the upper blocks A21, A22, A23, B21, and C21 of FIG. 4cannot be reference the blocks that may be referred to by the currentblock X2′. Therefore, the current block X2′ is coded in an intra mode.

Here, correlation is a concept identical to the correlation coefficientbetween two variables in stochastic probability theory. In this regard,correlation may denote the similarity between pixel values in a block inthe video processing field.

For example, when the pixel values of the current block are 255, 255,200, and 200, and a first neighboring block having pixel values of 255,255, 180, and 200 and a second neighboring block having pixel values of0, 150, 40, and 50 are present, it may be considered that the currentblock has a higher correlation with the first neighboring block.

Further, the above-described identical object region may be determinedusing depth information acquired by a depth camera, but thedetermination method is not limited thereto.

As described above, in the procedure for generating an inter-view motionmerge candidate, even if the reference block is intra-coded and thecurrent block is consequently unable to inherit motion information, thedevice and method for generating an inter-view motion merge candidateaccording to the embodiment of the present invention may inherit motioninformation from any of neighboring blocks of the reference block andperform a motion merge process. Due thereto, the device and method forgenerating an inter-view motion merge candidate may improve the encodingefficiency of the motion merge process for the current block. Also, thedevice and method for generating an inter-view motion merge candidatemay reduce computation complexity and memory complexity when encoding ordecoding is performed.

Here, encoding efficiency may be a value in which the difference invideo quality from original video and the bit rate of a compressed videostream are taken into consideration when video is compressed.

Further, the difference in video quality may be determined based on thePeak Signal-to-Noise Ratio (PSNR).

In this case, as the value of the PSNR increases, encoding efficiencyimproves, and similarly, as the value of the bit rate decreases,encoding efficiency improves.

Hereinafter, a device 500 and method for deriving an inter-view motionmerge candidate according to an embodiment of the present invention willbe described in detail.

FIG. 5 is a block diagram showing the device 500 for deriving aninter-view motion merge candidate according to an embodiment of thepresent invention.

Referring to FIG. 5, the device 500 for deriving an inter-view motionmerge candidate according to the embodiment of the present invention mayinclude a block search unit 510, an information analysis unit 520, and acandidate generation unit 530.

The block search unit 510 may individually acquire encoding informationfrom an inter-view reference block, derived through the disparity vectorof the current block, and from at least one neighboring block, which isspatially adjacent to the reference block.

The information analysis unit 520 may determine whether an inter-viewmotion merge process is possible for the current block based on theencoding information of the inter-view reference block.

More specifically, the information analysis unit 520 may determinewhether the inter-view reference block is intra-coded, based on theencoding information of the inter-view reference block.

For example, the information analysis unit 520 may perform determinationby referring to a header including a flag that indicates whetherencoding information is used. Here, the header may be a video parameterset extension. Further, the above-described encoding information of thereference block may include information about the motion and depth ofthe corresponding reference block.

Further, if it is determined that an inter-view motion merge process isimpossible for the current block, the candidate generation unit 530 maygenerate an inter-view motion merge candidate for the current blockusing the encoding information of a neighboring block. The encodinginformation of the neighboring block may include information about themotion and depth of the corresponding neighboring block.

In contrast, if it is determined that the inter-view motion mergeprocess is possible for the current block, the candidate generation unit530 may generate an inter-view motion merge candidate using the encodinginformation of the inter-view reference block.

Additionally, the candidate generation unit 530 may generate theinter-view motion merge candidate using the encoding information of ahighly correlated neighboring block included in an object regionincluding the inter-view reference block, among multiple neighboringblocks that are spatially adjacent to the inter-view reference block.

That is, in accordance with an example, the highly correlatedneighboring block may be determined depending on whether it is includedin the object region including the inter-view reference block, and theabove-described information may be used when the object region isdetermined.

Further, the candidate generation unit 530 may generate the candidateusing the encoding information of the highly correlated neighboringblock that is determined depending on the inheritance priority amongmultiple neighboring blocks that are spatially adjacent to theinter-view reference block.

Here, the inheritance priority may be preset in the sequence of aninter-view reference block, neighboring blocks that are encodedsubsequent to the inter-view reference block, and neighboring blocksthat are encoded prior to the inter-view reference block. Further, inaccordance with another example, the highly correlated neighboring blockmay be determined depending on the inheritance priority.

Furthermore, the device 500 for deriving an inter-view motion mergecandidate according to the embodiment of the present invention may beincluded in the video encoder 100, shown in FIG. 1, or the video decoder200, shown in FIG. 2. As an example, the device 500 for deriving aninter-view motion merge candidate may be installed as a single componentin the video encoder 100 or in the video decoder 200. As anotherexample, each component of the device 500 for deriving an inter-viewmotion merge candidate, or a program for performing the operation ofeach component, may be included in an existing component of the videoencoder 100, such as the prediction unit 110 or the adder 180, or in anexisting component of the video decoder 200, such as the prediction unit250 or the adder 240.

Next, a method for generating an inter-view motion merge candidateaccording to an embodiment of the present invention will be described indetail with reference to FIGS. 6 to 9.

FIG. 6 is a diagram showing the application of the method for generatingan inter-view motion merge candidate according to an embodiment of thepresent invention.

Referring to FIG. 6, when an inter-view motion merge candidate isgenerated for the current block X4 included in a current view frame 620,if a reference block X4′ in a previous view frame 610 is coded in anintra mode, the method for generating an inter-view motion mergecandidate may derive motion information of the current block X4according to the embodiment of the present invention.

Here, the above-described reference block X4′ may be the inter-viewreference block X4′ derived through the disparity vector 630 of thecurrent block X4.

When the reference block X4′ in the previous view frame 610, whichcorresponds to the current block X4 in the current view frame 620, iscoded in an intra mode, motion information is not present in thereference block X4′. Therefore, the conventional method cannot deriveinter-view motion information from the reference block X4′.

However, the method for generating an inter-view motion merge candidatemay use an inter-view motion merge process even if motion information isnot present, as in the case where the reference block X4′ is coded in anintra mode.

Further, in the method for generating an inter-view motion mergecandidate, blocks B43, C42 and C43, among the blocks, which are encodedsubsequent to the reference block X4′, belong to the same object as thereference block X4′, and then have higher correlation with the motioninformation of the current block X4.

Therefore, the method for generating an inter-view motion mergecandidate cannot derive motion information from the reference block X4′.However, in the method for generating an inter-view motion mergecandidate, if the motion information is derived from the blocks (B43,C42, or C43 block), which is encoded after the reference block X4′ hasbeen coded in an intra mode, that is, blocks (B43, C42, or C43 block)having higher correlation with the reference block, among neighboringblocks that are spatially adjacent to the reference block X4′,inter-view motion merge candidates having high encoding efficiency maybe used when inter-view motion merge candidates are generated.

FIG. 7 is a flowchart showing a method for generating an inter-viewmotion merge candidate according to an embodiment of the presentinvention.

Referring to FIG. 7, the method for deriving an inter-view motion mergecandidate according to the embodiment of the present invention maydetermine whether an inter-view motion merge process is possible for thecurrent block based on the encoding information of an inter-viewreference block, derived through the disparity vector of the currentblock at the current view (S720). Further, if it is determined that theinter-view motion merge process is impossible for the current block, themethod for generating an inter-view motion merge candidate may generatean inter-view motion merge candidate for the current block using theencoding information of a neighboring block that is spatially adjacentto the inter-view reference block (S750).

Further, the method for deriving an inter-view motion merge candidatemay calculate the position of the reference block in a previous view,corresponding to the current block, using the disparity vector of thecurrent block in the current view (S10).

In contrast, if it is determined that the inter-view motion mergeprocess is possible for the current block, an inter-view motion mergecandidate for the current block may be generated using the encodinginformation of the inter-view reference block (S730).

For example, the method for deriving an inter-view motion mergecandidate may determine whether the inter-view reference block isintra-coded, based on the encoding information of the inter-viewreference block, in order to determine whether the inter-view motionmerge process is possible for the current block based on the encodinginformation of the inter-view reference block, derived through thedisparity vector of the current block (S720).

Further, the method for deriving an inter-view motion merge candidatemay determine whether the inter-view motion merge process is possiblefor the current block based on the encoding information of theinter-view reference block, derived through the disparity vector of thecurrent block, and may determine whether the encoding information of aneighboring block is usable if it is impossible to use the referenceblock for the motion merge process (S740).

FIG. 8 illustrates a method for generating an inter-view motion mergecandidate according to another embodiment of the present invention.

Referring to FIG. 8, when an inter-view motion merge candidate isgenerated for the current block X6, which is included in a current viewframe 820, if a reference block X6′ in a previous view frame 810 iscoded in an intra mode, the method for generating an inter-view motionmerge candidate according to the embodiment of the present invention mayderive motion information of the current block X6.

Here, in the method for generating an inter-view motion merge candidate,when the inter-view motion merge candidate is generated for the currentblock X6, the reference block X6′, corresponding to the current blockX6, may be coded in an intra mode.

In this case, high priority may be assigned to blocks B63, C62, and C63,which are encoded after the reference block X6′ has been encoded, amongneighboring blocks that are spatially adjacent to the reference blockX6′.

Here, the above-described reference block X6′ may be an inter-viewreference block derived through the disparity vector 830 of the currentblock X6, and arrows 812, indicated in respective blocks, may denotepieces of motion information included in the above-described blocks,respectively.

A region 811 that is additionally shaded may be an object regionidentified using predetermined information. For example, thepredetermined information may be depth information input by a depthcamera.

FIG. 9 is a flowchart showing a method for generating an inter-viewmotion merge candidate according to another embodiment of the presentinvention.

Referring to FIG. 9, the method for deriving an inter-view motion mergecandidate according to another embodiment of the present invention maycalculate the position of a reference block at a previous viewcorresponding to the current block using the disparity vector of thecurrent block at the current view (S910), and may determine whether aninter-view motion merge process is possible for the current block basedon coding information of an inter-view reference block derived throughthe disparity vector of the current block at the current view (S920).Further, if it is determined that the inter-view motion merge process isimpossible for the current block, the method for deriving an inter-viewmotion merge candidate may generate an inter-view motion merge candidatefor the current block using coding information of a neighboring blockthat is spatially adjacent to the inter-view reference block (S950).

Further, the method for deriving an inter-view motion merge candidatemay generate an inter-view motion merge candidate for the current blockusing coding information of the inter-view reference block if it isdetermined that the inter-view motion merge process is possible for thecurrent block (S930).

For example, in order to determine whether the inter-view motion mergeprocess is possible for the current block based on coding information ofthe inter-view reference block derived through the disparity vector ofthe current block (S920), the method for deriving an inter-view motionmerge candidate may determine whether the inter-view reference block isintra-coded, based on coding information of the inter-view referenceblock.

Further, if it is determined that it is impossible to use the referenceblock for the motion merge process, the method for deriving aninter-view motion merge candidate may determine whether it is possibleto use at least one of neighboring blocks that have been encodedsubsequent to the reference block for a motion merge process (S940).

Next, if it is determined that it is impossible to use at least one ofneighboring blocks that have been encoded subsequent to the referenceblock for the motion merge process, the method for deriving aninter-view motion merge candidate may determine whether it is possibleto use for at least one of neighboring blocks that have been encodedprior to the reference block for the motion merge process (S960).

Here, if it is determined that it is possible to use at least one ofneighboring blocks that have been encoded prior to the reference blockfor the motion merge process, the method for deriving an inter-viewmotion merge candidate may generate an inter-view motion merge candidatefrom the neighboring block (S970).

The components included in embodiments of the present invention are notlimited to software or hardware, and may be configured to be stored inaddressable storage media and to execute on one or more processors.

Therefore, as an example, the components may include components such assoftware components, object-oriented software components, classcomponents, and task components, processes, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuitry, data, databases, data structures, tables, arrays,and variables.

The components and functionality provided in the correspondingcomponents may be combined into fewer components, or may be furtherseparated into additional components.

The embodiments of the present invention may also be implemented in theform of storage media including instructions that are executed by acomputer, such as program modules executed by the computer. Thecomputer-readable media may be arbitrary available media that can beaccessed by the computer, and may include all of volatile andnonvolatile media and removable and non-removable media. Further, thecomputer-readable media may include all of computer storage media andcommunication media. The computer-storage media include all of volatileand nonvolatile media and removable and non-removable media, which areimplemented using any method or technology for storing information, suchas computer-readable instructions, data structures, program modules oradditional data. The communication media typically include transmissionmedia for computer-readable instructions, data structures, programmodules or additional data for modulated data signals, such as carrierwaves, or additional transmission mechanisms, and include arbitraryinformation delivery media.

The above-described method for generating an inter-view motion mergecandidate according to the present invention can be implemented ascomputer-readable code in computer-readable storage media. Thecomputer-readable storage media include all types of storage media inwhich data that can be interpreted by a computer system is stored.Examples of the computer-readable storage media may include Read-OnlyMemory (ROM), Random-Access Memory (RAM), magnetic tape, a magneticdisk, flash memory, an optical data storage device, etc. Further, thecomputer-readable storage media may be distributed across computersystems connected through a computer communication network, and may bestored and executed as code that is readable in a distributed manner.

Although the method and system of the present invention have beendescribed in relation to specific embodiments, the some or all of thecomponents or operations thereof may be implemented using a computersystem that has general-purpose hardware architecture.

The description of the present invention is intended for illustration,and those skilled in the art will appreciate that the present inventioncan be easily modified in other detailed forms without changing thetechnical spirit or essential features of the present invention.Therefore, the above-described embodiments should be understood as beingexemplary rather than restrictive. For example, each component describedas a single component may be distributed and practiced, and similarly,components described as being distributed may also be practiced in anintegrated form.

The scope of the present invention should be defined by the accompanyingclaims rather than by the detailed description, and all changes ormodifications derived from the meanings and scopes of the claims andequivalents thereof should be construed as being included in the scopeof the present invention.

What is claimed is:
 1. A method for decoding a video signal comprising:determining a reference block corresponding to a current block;determining whether motion information of the reference block isavailable for deriving motion information of the current block, based onmotion information of the reference block; and deriving the motioninformation of the current block using coding information of a blockspatially adjacent to the reference block, when the motion informationof the reference block is not available for deriving motion informationof the current block.
 2. The method of claim 1, further comprises,deriving the motion information of the current block by using the motioninformation of the reference block, when the motion information of thereference block is available for deriving motion information of thecurrent block.
 3. The method of claim 1, wherein whether motioninformation of the reference block is available for deriving motioninformation of the current block is determined based on whether thereference block is inter-coded or not.
 4. A method for encoding a videosignal comprising: determining a reference block corresponding to acurrent block; determining whether motion information of the referenceblock is available for deriving motion information of the current block,based on motion information of the reference block; and deriving themotion information of the current block using coding information of ablock spatially adjacent to the reference block, when the motioninformation of the reference block is not available for deriving motioninformation of the current block.
 5. A computer-readable recordingmedium storing a bitstream which is received and decoded by an imagedecoding apparatus, and used to reconstruct an image, wherein thebitstream comprises information related to a current block, wherein theinformation related to the current block is used to determine areference block corresponding to the current block in a decodingprocess, wherein coding information of the reference block is used todetermine whether motion information of the reference block is availablefor deriving motion information of the current block in the decodingprocess, and wherein when the motion information of the reference blockis not available for deriving motion information of the current block,the motion information of the current block is derived using codinginformation of a block spatially adjacent to the reference block in thedecoding process.